#include <STC89C5xRC.H>

void Delay(unsigned int xms)	//@12.000MHz
{
	unsigned char data i, j;

	while(xms--){
        i = 2;
        j = 239;
        do
        {
            while (--j);
        } while (--i);
    }
}

void main(){

	while(1){
		if(P31 == 0){
			Delay(20);
			while(P31 == 0);
			Delay(20);
			P24 = ~P24;
		}
	}
}